Lemania, tonneau-shaped, self-winding, water-resistant, stainless steel wristwatch with day & date, round button chronograph, registers, central minute counter, with inner minute bezel.
Case: Two-body, brushed, screw-down case back and crown, inner graduated bidirectional revolving disc, sapphire crystal.
Dial: Black with painted luminous baton indexes and 1/5th seconds track, subsidiary dials for the seconds and the 12-hour registers, outer rotating disc. Central orange 60 minute marker and chronograph hand Luminous white baton hands.
Movement: Caliber Lemania 5100, rhodium-plated, 17 jewels, straight line lever escapement, monometallic balance, shock absorber, self-compensating flat balance spring, hack mechanism.
Dial, case and movement signed.
Some scratches on original glass and case. Overall condition is good
Diam. 44 mm and Thickness: 15 mm.
The Lemania 5100 was discontinued about 15 years ago after 30 years of service. It is considered a legendary chronograph by most collectors. It has an unusual; construction, a navette-type chronograph mechanism fitted between the dial and the base plate. The 5100 rotor winds in one direction only over the reduction gear and runs in a hard iron bearing instead of jewels. The ratchet wheel under the rotor transfers the rotation of the rotor to a reduced wheel. It clearly shows that the Lemania 5100’s antiquated construction, is simple, reliable and functional.
The 5100 is the only calibre that met some countries military requirements due to its construction. It is the only chronograph movement that can withstand large shocks without its chronograph seconds hand stopping. This is because its chronograph mechanism is driven directly unlike other chronographs which use an intermediate wheel. The calibre easily withstands acceleration in excess of 7G without appreciable loss of accuracy. Its ruggedness is legendary; the calibre easily absorbs shocks and blows. The calibre also maintains its accuracy over long periods without servicing. Service intervals from four to seven years have shown to be sufficient.
The calibre 5100 is most often seen in watches from Sinn, Fortis, Omega and Bell & Ross but rarely in a Lemania signed watch.